carbide drill bits?

M

mitch8

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Oct 11, 2010
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i'm wearing out all my titanium nitride bits on this chunk of O1 and its still not going through. should i go buy some carbide bits? what should i expect to pay? what kind of carbide or coating should i buy?

mitch
 
I like carbide drill bits for abrasive applications like production runs in plastic. I've never had much use for them in steel.

What's wrong with your O1 that a regular quality cobalt HSS bit doesn't work?

I've seen tin coated bits that were real junk so that gold coating doesn't mean anything. Look for American made HSS bits and you should be fine unless the work piece is hardened.

Unless you're doing lots of hundreds of parts at a time, a regular black oxide HSS is all you want for steel. I can get several hundred holes in D2 with a $3.00 bit.
 
I'm pretty much with Nathan on this. I use cobalt steel bits from Enco and easily get several hundred holes per bit. Is it possible you're drilling too slowly yet building up enough heat to work harden the steel. I don't use O1, but I regularly drill lots of holes in D2 and CPM 3V with cobalt bits, no problem.

What size hole are you drilling? If it's bigger than 3/16" or so, are you starting with a smaller bit and working you way up to the desired size? Sometimes you can run into problems if you try to drill a 5/16" or 3/8" hole in just one pass.

The only time I've ever needed carbide is when I'm milling or when I'm drilling something like a detent hole in a hardened folder blade.
 
the O1 was forged so i'm not sure how that would affect the drilling. and i'm drilling 1/4 and 5/16 inch holes for a brass pin. that enco site has a lot of different types of bits, any direction for what i should buy?
 
couple of things here. O-1 has an air hardening tendency. Many won't use it because of this. You need to do a good anneal preferably a full spherodized anneal. Also it can be work hardening. Keep a steady pressure, do not let the drill dwell in the hole. Sharp stops will break the chip but apply pressure once the chip breaks. But with 1.4 inch thick material the chip won't be too bad. Also you might be running the drill too fast. A 1/4 inch HSS bit should be run around 800-1000 rpm in O-1. If all this fails and you are using quality bits you might have to go with carbides. I have punched holes in hardened steel using end mills. But you need a mill for this a drill press is not rigid enough. Good luck and let us know how things go. If you need help drop me a PM and I would be happy to put some holes in it for you.
 
i just "annealed" it by heating it to red orange in a propane oven and then transferring it to a covered hotplate full of sand turned to 420f to cool. i haven't put much money into my knife making.
 
That can be a problem with O-1. It takes a bit more control to get it soft enough to drill/file. L6 is another one that causes problems.
 
It can be done with simple tools/forge. Invest $100 in a Thermocouple and readout. Then you can step down the heat a bit slower and get soft enough to work. If you are really good at judging temps or use a magnet try a few cycles just above austenizing and then a couple just below. This might get you soft enough to drill.
 
My experience with TiN is the same as Nathan's . It came off quickly so I never used it again !!
 
re: fancy drill bits

Last week I setup a production job in my shop. There were a bunch of roll formed 1/4-20 holes so I order a zrn coated powered metal split point parabolic drill, probably a $15 cutter. The job is 6061 aluminum so I'm feeding this badboy at 41 IPM at 4500 RPM. Think about that second, forty one inches per minute feed rate. That is one 3/4" deep hole per second. Well, I made a programming error and didn't retract in Z far enough to clear a feature and broke the bit on the first part. I didn't have another fancy drill bit in that size so I pulled a regular 118 deg black oxide HSS drill out of the drill box and used a plain jane drill for the rest of the production run but still fed it at 41 IPM and it didn't give me any problems.

I am increasingly of the opinion that fancy drills aren't always necessary and a good quality regular HSS drill works pretty well (stay away from cheap chicom or India crap).
 
I had a knife I was working on this morning ( at 6AM). The tang holes were about 5/32, and the blade was hardened. I decided to use Corby bolts with 3/16 shanks. I used a 3/16 spade bit at 1500 RPM and drilled out the holes in a few seconds. I have several types of carbide bits, and they all have specific uses, but for people with a basic drill press and limited skills, a spade bit is a good choice.
 
I use carbide tipped Masonry Drill Bits for drilling hardened steel. They're much cheaper and if you drill slow, they work quite well.
Just don't "burn" them.
 
@Nathan, and that is the truth ... amen

good reg bits are the way

save the chicoms for drilling spruce 2x4's
 
yeah i was wondering about using a cheap masonry drill bit. what rpm are running those at, parbajtor?

bladsmth, are you kidding about the spade bit or is there a spade made for metal drilling that i don't know about?

can anyone tell me the differences in the coatings?

and lastly do any of the bits in the links i posted above look like there worth there salt?
 
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are there any HSS that are better than others? what kind of high speed steel should i be searching for in drill bits?
 
I tend to just buy multiples of the bits I use the most from Enco in lieu of buying them in a large set. I buy the Hertel brand and I find them better than the "Import" or "Enco" bits by at least as much as they cost more....although I hear that the Precision Twist are better and worth the extra pennies.
 
Mitch
The bits in the first 2 links are Made in China crap,the third link are cobalt but have not used any from that oufit.
I get all my bits from Enco,buy made in usa or similar,buy only the sizes you use and buy mutiple.
Also buy screw machine lenght,they are shorter and won't walk or break as easily.
http://www.use-enco.com/CGI/INSRAR?PMSECT=0000000623
Stan
 
thanks guys! looks like ill pick up some cobalt bits from enco. there is the uncoated enco brand for 2.38 or the uncoated hertel 4.65
any recriminations?
 
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